The invention relates to improved cleaning compositions for hard surfaces and methods of their manufacture. Further, the invention also relates to solid block cleaning compositions containing acidic components. Still further, the invention relates to acidic solid block cleaning compositions that can contain a variety of optional ingredients which may be used to enhance or broaden the soil removing activity of the acid components. The invention also relates to methods of cleaning hard surfaces comprising dispensing a concentrate by contacting the acid block detergent with an aqueous spray, diluting the concentrate with an appropriate amount of an aqueous diluent to produce an acid cleaning product and applying the product to a soiled surface to remove the soil.
Hard surface cleaners useful in institutional and non-institutional environments may take any number of forms. Typically these cleaners are liquid formulations as either a non-aqueous, organic cleaner formulation, or aqueous cleaner formulations that can be neutral, acidic or alkaline in pH when diluted to use solutions. Organic cleaner formulations are commonly prepared in an organic base material such as a solvent or surfactant base. Further these formulations may comprise a variety of ingredients such as sequestrants, rust inhibitors, etc.
Aqueous, neutral, acid, or alkaline cleaners, in use solution concentrations, are typically formulated, using a major proportion of an aqueous diluent and minor, but effective amounts, of surfactants, cosolvents and sequestrants. In large part, these cleaners can be used in the form of an aqueous liquid concentrate that is diluted with water to form the use solution. These dilute liquid cleaning formulations have been useful in a number of cleaning environments. However, dilute liquid cleaning formulations that contain a substantial proportion of an aqueous or organic diluent often entails large transportation costs to move solvent or water. Further, cleaning concentrates in liquid form can often be contaminated or can in some cases deteriorate, phase separate and become useless. Further, liquid materials can spill, splash or otherwise be misused resulting in a safety hazard in contact between users and the alkaline or acid concentrate materials.
A number of aqueous acidic cleaners have been disclosed in the prior art. While there are a large number of patents teaching acid cleaners, the following are representative. Casey, U.S. Pat. No. 4,587,030 teaches a foamable acidic liquid cleaning composition adapted for cleaning soap scum and other hardness components from hard surfaces. The cleaners contain a mixture of oleic organic acid and oleic inorganic acid, a surfactant system and a cosolvent that is particularly adapted to removing soap scum that forms in kitchens, baths, etc. Copeland, U.S. Pat. No. 4,769,159 teaches an institutional fabric softening containing cationic surfactant and organic acid in the form of a stable solid block material comprising acidic fabric softening components. Cockrell, Jr. et al., U.S. Pat. Nos. 4,877,459 and 4,749,508 teach liquid acidic materials for cleaning hard surfaces and in particular quarry tile surfaces. The patents teach specific compositions and generic methods using an acid cleaner for soil removal. Gladfelter, U.S. Pat. No. 5,198,198 teaches generic cleaner compositions manufactured in the form of a pellet material formed inside a water soluble bag. The pellets can have acid components. Inorganic alkaline cast solid materials can be formed using known technologies. Fernholz, U.S. Reissue Patent No. 32,818 teaches a solid block detergent containing large proportions of caustic. Morganson et al, U.S. Patent No. 4,624,713 teaches a solid rinse agent containing a rate dispensing agent for varying the release of the surfactant rinse agent. Heile et al., U.S. Pat. Nos. 4,680,134 and 4,595,520 teaches a lower alkaline detergent which optionally contains various inorganic solids. Solid inorganic fertilizer materials are disclosed in Jordan et al., U.S. Pat. No. 4,175,943; Corver et al., U.S. Pat. No. 4,260,592 and Khasawneh, United States Defensive Publication No. T102902. These patent disclosure documents are primarily directed to particulate inorganic fertilizer compositions containing a blend of materials optimized for fertilizing growing plant tissue. These formulations are not highly acid, nor do they contain components that contribute the cleaning performance of acidic cleaners.
While liquid aqueous acidic cleaners have had success in removing soil from a variety of hard surfaces, the aqueous liquid materials still pose a substantial drawback to a user based on both economic and safety considerations. Accordingly, a substantial need exists in improving acid cleaners to render them more cost effective and safe.
The invention comprises a solid block acid cleaner comprising a solid matrix including a blend of an acid cleaner component, a surfactant composition selected from the group consisting of an anionic surfactant, a nonionic surfactant or mixtures thereof, and a binding agent or solidification compound resulting in a solid mass of about 100 grams or more. The invention also resides in a preferred solid block acid cleaner composition comprising an acid source which is a solid or substantially a solid at any temperature less than 40xc2x0 C., and an acid which can exist as a liquid at a temperature less than about 40xc2x0 C., a surfactant composition having a nonionic selected from the group consisting of an alcohl ethoxlyate, a nonylphenol ethoxylate, an ethoxylated/propoxylated copolymer, and mixtures thereof, and an anionic surfactant selected from the group consisting of alkylsulfate or sulfonate, arylsulfate or sulfonate, alkylaryl sulfate or sulfonate, and mixtures thereof and a solidification compound preferably urea, wherein said solid block acid cleaning composition has a pKa ranging from about 1 to 3. The invention also includes methods of use and manufacture for the composition of the invention.
We have found a unique product format comprising a solid block cleaner composition that when diluted with water (at about 1 wt-% active aqueous solution) produces a product or use solution that exhibits a pH less than about 6. The solid block detergent can contain acids that are normally liquid and acids that are normally solid at room temperature. The solid matrix can be dispensed from the solid state to form an aqueous concentrate having a substantial proportion of acid components plus other additives that can enhance or extend the performance of the acid cleaner material. Such concentrate materials can be further diluted with water to form a use solution. In use, the composition of the invention may be applied to any number of surfaces including floors, counter tops, cleaning and food preparation surfaces, among other materials. Such use solutions can be applied to a variety of hard surfaces in the institutional, hospitality or industrial markets for removal of a variety of soil types.
Further, the invention relates to methods of manufacturing a solid block acid cleaner material. Such materials can contain one or more sources of acidity, solvent or co-solvent, additive detergent or surfactant materials and a solidification agent. The formulated acidic material solidifies through the interaction of the intentionally blended components and can be solidified within a disposable container, a film, a water soluble wrapping material or can be packaged in other convenient packaging material. For the purpose of the materials used in making the acid cleaner of the invention and the acid cleaner of the invention, a xe2x80x9csolidxe2x80x9d is a composition that, at use temperature, is sufficiently resistant to flow that the unsupported composition will not substantially change shape upon standing. Such a solid can be in the form of a matrix including a hard block or brick or a deformable but rigid aqueous dispersion or hard gel. For the purposes of this invention, a liquid is a material that flows at a substantial rate, at use temperature, such that the unsupported material (removed from a container) will lose its shape upon standing in less than one minute. A matrix can comprise a solid mass or a solidified blend of materials having various particle sizes and states of solidification and can comprise liquid components in the solid in a form and concentration that do not interfere with maintaining a stable solid. The matrix can be made by casting, compressing, pelletizing, etc.